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The Single UNIX &reg; Specification, Version 2<br>
Copyright &copy; 1997 The Open Group

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<h4><a name = "tag_000_010_289">&nbsp;</a>NAME</h4><blockquote>
unlockpt - unlock a pseudo-terminal master/slave pair
</blockquote><h4><a name = "tag_000_010_290">&nbsp;</a>SYNOPSIS</h4><blockquote>
<pre><code>

#include &lt;<a href="stdlib.h.html">stdlib.h</a>&gt;

int unlockpt(int <i>fildes</i>);
</code>
</pre>
</blockquote><h4><a name = "tag_000_010_291">&nbsp;</a>DESCRIPTION</h4><blockquote>
The
<i>unlockpt()</i>
function unlocks the slave pseudo-terminal device associated with the master
to which <i>fildes</i> refers.
<p>
Portable applications must call
<i>unlockpt()</i>
before opening the slave side of a pseudo-terminal device.
</blockquote><h4><a name = "tag_000_010_292">&nbsp;</a>RETURN VALUE</h4><blockquote>
Upon successful completion,
<i>unlockpt()</i>
returns 0.  Otherwise, it returns -1 and sets
<i>errno</i>
to indicate the error.
</blockquote><h4><a name = "tag_000_010_293">&nbsp;</a>ERRORS</h4><blockquote>
The
<i>unlockpt()</i>
function may fail if:
<dl compact>

<dt>[EBADF]<dd>
The <i>fildes</i> argument is not a file descriptor open for writing.

<dt>[EINVAL]<dd>
The <i>fildes</i> argument is not associated with a master pseudo-terminal
device.

</dl>
</blockquote><h4><a name = "tag_000_010_294">&nbsp;</a>EXAMPLES</h4><blockquote>
None.
</blockquote><h4><a name = "tag_000_010_295">&nbsp;</a>APPLICATION USAGE</h4><blockquote>
None.
</blockquote><h4><a name = "tag_000_010_296">&nbsp;</a>FUTURE DIRECTIONS</h4><blockquote>
None.
</blockquote><h4><a name = "tag_000_010_297">&nbsp;</a>SEE ALSO</h4><blockquote>
<i><a href="grantpt.html">grantpt()</a></i>,
<i><a href="open.html">open()</a></i>,
<i><a href="ptsname.html">ptsname()</a></i>,
<i><a href="stdlib.h.html">&lt;stdlib.h&gt;</a></i>.
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UNIX &reg; is a registered Trademark of The Open Group.<br>
Copyright &copy; 1997 The Open Group
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